Redox-sensitive trace element geochemistry reveals intermittent water column stratification in Cretaceous Songliao Paleo-lake: evidence from marginal facies of members 1 and 2 of Qingshankou Formation 
Zhang Haiyang 1, 2, 3, 4 , Fang Shi 1, 2, 3 ∗, Zhang Hao 1, 2, 3 , Wang Qingfeng 1, 2, 3 , Zhang Peng 5 , Ma Peisong 5
World Geology . 0, (): 1 .